MFC Debug Assertion Failed (DLL Dialog Create Error)

Question

I am trying to CREATE a dialog as MODALESS in a DLL. When DEBUGING is attempted, DEBUG ASSERTION FAILED LINE24 is output. What should I do?

Code Example :
extern "C" __declspec(dllexport) int CreateDlg()
{
CTestDlg *pDlg = new CTestDlg;

pDlg->Create(IDD_DIALOG1); // This Code Error Message Print  
  
return 0;  

}

Answer 1

When you export a function from a regular MFC DLL the function must include AFX_MANAGE_STATE.

For example,

   extern "C" __declspec(dllexport) int CreateDlg()  
   {  
   	AFX_MANAGE_STATE(AfxGetStaticModuleState());  
     
   	CModeless* pdlg = new CModeless;  
   	pdlg->Create(IDD_MODELESS);  
   	pdlg->ShowWindow(SW_SHOW);  
   	return 0;  
   }  

Answer 2

Hi @채문석(jim) ,

If you are trying to dynamically create a modeless dialog the following steps are required:

Create a dialog box in the resource file, then right-click to select Add Class

Add the header file of the dialog class in the .cpp file and then use the following code.

CMyDlg *dlg = new CMyDlg;  
dlg->Create(IDD_DIALOG1, NULL);  
dlg->ShowWindow(SW_SHOW);  

Best regards,

Elya

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